Abu Dhabi prosecutors have detained a member of their own ruling family after a video (available on youtube, but it is highly disburbing and we recommend you do not watch) was circulated showing him torturing a man.
Public prosecutors say they also have begun criminal inquiries into Issa bin Zayed al-Nahyanâ€™s actions on the tape.
The investigation is the first reported of a ruling family member in Abu Dhabi, capital of the United Arab Emirates.
Previously, Emirati officials had named Sheikh Issa as the man in the video but said the case was â€œresolved privately.â€
â€œThe Public Prosecution Office has officially launched a criminal investigation into the events depicted on video and detained Sheikh Issa bin Zayed al-Nahyan pending the outcome of this investigation,â€ the official news agency WAM reported on Monday.
â€œThis is to ensure that all human rights obligations are met and enforced, that all national laws are applied equally and with transparency to all,â€ WAM said, quoting a statement by the Judicial Department.
On 30 April, after initially dismissing accusations about the video, the Abu Dhabi authorities condemned the torture depicted in the tape and called an inquiry into the case.
The advocacy organization Human Rights Watch described reports of the sheikhâ€™s detention as reassuring, but called on the Emirates government to demonstrate complete transparency in the case.
â€œSecretive prosecutions will not deter further abuses,â€ said Human Rights Watch Middle East director Sarah Leah Whitson.
The video shows Sheikh Issa repeatedly beating the man, Mohammed Shah Poor, a grain merchant of Afghan origin, and running him over with a car. Several other men assist in the tape, including one in a uniform of the security forces.
The incident, said to have taken place in 2004, came to light after US television network ABC broadcast clips of the tape, which was smuggled out of the UAE by a former business associate of Issa bin Zayed al-Nahyan.
Reports say the merchant had lost a consignment of grain belonging to Sheikh Issa worth $5,000 (Â£3,300). He survived the abuse, but needed extensive hospital treatment.
In a letter to ABC News, the UAE authorities initially said a police investigation that cleared the sheikh had â€œcorrectly followed… all rules, policies and proceduresâ€ set out by the Police department.